Charles Ellicott Commentary 1 Chronicles 12:7

"and Joelah, and Zebadiah, the sons of Jeroham of Gedor." — 1 Chronicles 12:7 (ASV)

Sons of Jeroham of Gedor. —Jeroham is the name of a Benjamite clan (1 Chronicles 8:27); and two Benjamite chiefs are called “Zebadiah” (1 Chronicles 8:15; 1 Chronicles 8:17). On the other hand, “Gedor” was a town of Judah, south-west of Bethlehem (1 Chronicles 4:4).

Some account for the appearance of Judean names in a list purporting to relate to Benjamites by the assumption that the chronicler has welded two lists into one. But towns did not always continue in the hands of the tribes to whom they were originally intended, and some Judean towns may have contained a partially Benjaminite population.